The common practice in handling fibrous mineral blankets, particularly fibrous mineral blankets suitable for insulation purposes, is for the fibrous mineral blanket to be conveyed into contact with means such as a rotary saw for continuously slitting the fibrous mineral blanket into narrower strips, such as batts. Subsequent to the slitting process, the batts are commonly separated from each other by coming into contact with wedge-shaped spreaders. Thereafter, facing materials, such as kraft paper or foil, are usually applied separately to each batt in a continuous process. The batts are then cut into lengths and packaged.
One of the problems associated with such fiber handling processes is the problem of dust and particulate mineral fiber material generated by the slitting saws. Since the slitting process is continuous, and since the individual mineral fibers are fragile, large amounts of mineral dust are generated. The mineral fiber dust is often quite fine because the mineral fibers themselves can have an average diameter of about seven microns or less prior to the slitting step. The majority of the mineral fiber dust is retained at the side edges of the batts, and this has been found to be undesirable because the mineral fiber dust tends to foul apparatus in subsequent fabrication operations, such as in applying the facings to the batt, and in packaging the batts. Those who install the fibrous mineral products in their ultimate destinations, such as new housing construction, mobile homes or retrofit installations, find the presence of such a large amount of mineral fiber dust to be highly objectionable. Also, the slitter saws generate numerous tiny, loose insulation clumps, referred to as "puff balls," which adhere to the side edges of the batts and which are undesirable from a process and asthetic point of view. Additionally, the presence of mineral fiber dust particles during insulation fabrication processes create objectionable air pollution problems. There is a need for apparatus for effectively removing loose mineral fiber particles from the edges of the newly slit batts.